The present invention is in the field of packaging fluid-tight and impermeable barriers. It is directed more precisely to an inflatable and deformable piston, particularly for producing a fluid-tight impermeable barrier for a container, for example packages of the type for aerosols.
The technique of piston type containers in which a container, for example in monocompartmental aerosol packaging is converted into a two-compartment housing, is known, but until now, no realization thereof gave satisfaction due to the fact that complete fluid-tightness between the two compartments separated by the piston was not ensured. In the same way, the constructions of the prior art did not permit the introduction of the piston through the neck of the housing, considering that pistons used until then did not have the appropriate flexibility. In the more particular field of piston-type aerosol packages, there does not exist at present on the market any container or packaging capable of ensuring perfect fluidtightness between the two compartments, which limits the use of this technology and particularly its employment for aerosol packaging, to liquids or fluids of low viscosity or not wetting the walls of the piston and of the container. In fact, these pistons are formed of plastics material of little flexibility, the sealing between the two compartments, namely the compartment containing the product ant that containing the propellant gas, being ensured by the formation of a film of the product between the wall of the piston and that of the packaging container. Moreover, the plastics materials used are fairly permeable to the propellants or altered by humidity. It will also be noted that this films serving for the fluidtightness does not ensure the latter perfectly considering that it is more or less permeable to the propellant gases.